By the way, it's just a question I've had on my mind, but is it the new police procedure to just file the warrant for the arrest without even bothering to question the suspects? Does anybody know, have a LE background, have a J.D.? I can't even envision that as being logical, but I realize my mind doesn't work the way others do.
It is not normal at all, and goes against all professional investigative procedures.
Nifrong's handling of the case makes sense if, and only if, he knows that the defendants are innocent. Viewed in that light, his actions, while inept, are perfectly logical (subject to the constraints of his ineptness).
Prosecutors love it when guilty defendants talk. Especially when the defendants try to spin cover stories. Very few guilty defendants can fabricate a consistent cover story without slipping up, and slip-ups by the defense are good for the prosecution. So if Nifrong thought the students were guilty, why wouldn't he want them to talk to him?
The most logical explanation is that he knows full well that if one or more of the students has a good honest alibi he might have a hard time claiming he believes them guilty. He further knows that if any of Precious' identifications is proven to be wrong, they all become even more dubious than they are.
I don't know what Nifrong is planning, though if I were one of the students I might look into getting some body armor. I don't see much of an out for Nifrong as long as the students are alive.